Palletizers are used to load pallets with cartons, bags, bundles, or other packages. Some standard types of palletizers include stripper plate palletizers, pick and place palletizers, and row picker palletizers. A stripper plate palletizer builds a palletized load a full layer at a time. Typically, it builds the layer on a plate, and the entire layer is then pushed off the plate onto a pallet by a stripper mechanism. A pick and place palletizer builds a palletized load one product unit at a time. It may include a gantry and/or robotic arm that picks up the product unit and then places the product unit in the proper location on the load. A row picker palletizer builds a palletized load one row at a time. It uses a row securing system, such as a clamp, to pick up, transport, and place a single, complete row of product on the pallet.
Regardless of the type, palletizers are typically programmed with a loading sequence to build the load. The palletizers follow the sequence to place one product unit, or one set of product units, at a time in a location on the pallet specifically programmed in the sequence. Accordingly, the palletizer follows one part of the sequence to place a first product unit in a first location, and follows a second part of the sequence to place a second product unit in a second location. When the palletizer has followed the complete sequence, placing product units in each assigned location, the palletized load is complete. Typically, the sequence counts the numbers of product units in a row, the number of product units in a layer, and the number of layers in the palletized load. For example, a pick and place palletizer may be programmed to build a row on the palletized load by following a sequence five times to complete the row having five product units.
Often, product manufacturers use a single palletizer to load different sized products at different times. To do this, the palletizer must be adapted to changeover from one product to another, and build palletized loads with the different sized products. Because building the load requires that product units to be placed in assigned locations, changeover from one size or shape of product to another typically requires a new computer program setting forth a new sequence for the product, which is determined by the size and shape of the product. Accordingly, when the product size is changed, or the orientation of the product is changed, the sequence must also be changed. For example, if the palletizer is set to load twelve inch product units, then loading product either larger or smaller than twelve inches may cause either interference between the product units, or gaps between the product units on the palletized load unless the sequence program is changed.
Preparing and programming a new sequence for each change in product size can be an expensive and a complex procedure, furthermore, frequent changeover using complex systems can be prone to errors and may result in downtime and/or other inefficiencies.
The present invention overcomes one or more of the deficiencies in the prior art.